Repair animated billboard

I have the 6-12761 animated billboard. It stopped working yesterday.  When you turn it on,  it switches the billboard right away but then does nothing else.  Normally,  it fires right away and then every few seconds it fires to switch the billboard back and forth.  Turning it off and then back on it will fire initially and then nothing. It will consistently fire when power is first applied, then nothing.  I opened it up and it has a very basic circuit. Based on the picture,  could it be one of the mofsets? @gunrunnerjohn If so,  what is a suitable replacement,  as they have been discontinued.  I can solder in new parts,  just not sure how to diagnose it.